package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.Voucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IVoucherService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 硕哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    public static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    public void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true){
                try {
                    //1.从消息队列中获取订单
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息是否获取成功
                    if (list==null||list.isEmpty()){
                        //2.1 失败,继续下一个循环
                        continue;
                    }
                    //2.2 成功,解析并创建订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    handleVoucherOrder(voucherOrder);
                    //3 ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true){
                try {
                    //1.从pending-list中获取订单
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息是否获取成功
                    if (list==null||list.isEmpty()){
                       break;
                    }
                    //2.2 成功,解析并创建订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    handleVoucherOrder(voucherOrder);
                    //3 ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list异常",e);
                    continue;
                }
            }
        }
    }
//    BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VoucherOrderHandler implements Runnable{
//        @Override
//        public void run() {
//            while (true){
//                try {
//                    //1.获取队列中的订单
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    //2.创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常",e);
//                }
//            }
//        }
//    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        //2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.尝试获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取成功
        if(!isLock){
            //获取锁失败,直接返回失败或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            //5.成功,创建订单
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //6.释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId));
        // 2.判断结果是否为0
        if (result.intValue() != 0) {
            //2.1结果不是0
            return Result.fail(result == 1 ? "库存不足" : "重复下单");
        }
        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 1.执行lua脚本
//        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), UserHolder.getUser().getId().toString());
//        // 2.判断结果是否为0
//        if (result.intValue() != 0) {
//            //2.1结果不是0
//            return Result.fail(result == 1 ? "库存不足" : "重复下单");
//        }
//        // 2.2结果是0,保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//
//        Long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        voucherOrder.setUserId(UserHolder.getUser().getId());
//        voucherOrder.setVoucherId(voucherId);
//        //3.添加到阻塞队列
//        orderTasks.add(voucherOrder);
//        //获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        //4.返回订单id
//        return Result.ok(orderId);
//    }

    @Override
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //8 一人一单
        Long userId =voucherOrder.getUserId();
        //8.1查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //8.2判断是否存在
        if(count > 0){
            //用户已经购买过了
            log.error("用户已经购买过一次了");
            return;
        }
        //5.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")//set
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0)//where
                .update();
        if(!success){
            log.error("库存不足");
            return;
        }
        //6.4保存订单
        save(voucherOrder);
        return;
    }
}

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        if(voucher == null){
//            return Result.fail("优惠券不存在");
//        }
//        //2.判断秒杀是否开始
//        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀未开始");
//        }
//        //3.判断秒杀是否结束
//        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已结束");
//        }
//        //4.判断库存是否充足
//        if(voucher.getStock() < 1){
//            return Result.fail("库存不足");
//        }
//        //利用用户id构造悲观锁
//        Long userId = UserHolder.getUser().getId();
//        //6.创建锁对象
//        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //7.尝试获取锁
//        boolean isLock = lock.tryLock();
//        //8.判断是否获取成功
//        if(!isLock){
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            //5.调用代理对象的方法,才能使事务管理生效
//            return proxy.createVoucherOrder(voucherId);
//        } catch (IllegalStateException e) {
//            throw new RuntimeException(e);
//        } finally {
//            lock.unlock();
//        }
//    }
//
//    @Transactional
//    public Result createVoucherOrder(Long voucherId) {
//        //8 一人一单
//        Long userId = UserHolder.getUser().getId();
//        //8.1查询订单
//        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
//        //8.2判断是否存在
//        if(count > 0){
//            //用户已经购买过了
//            return Result.fail("用户已经购买过一次了");
//        }
//        //5.扣减库存
//        boolean success = seckillVoucherService.update()
//                .setSql("stock = stock - 1")//set
//                .eq("voucher_id", voucherId).gt("stock",0)//where
//                .update();
//        if(!success){
//            return Result.fail("库存不足");
//        }
//        //6.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //6.1生成订单id
//        long orderId = redisIdWorker.nextId("voucherOrder");
//        voucherOrder.setId(orderId);
//        //6.2获取用户id
//        voucherOrder.setUserId(userId);
//        //6.3设置代金券id
//        voucherOrder.setVoucherId(voucherId);
//        //6.4保存订单
//        save(voucherOrder);
//        //7.返回订单id
//        return Result.ok(orderId);
//    }
//}
